In a world of constant human-machine interaction, appropriate isolation measures are of paramount importance. Miles of wiring connect switches, sensors, and high-voltage motors in electric vehicles. Industrial controllers exchange data, commands, and power with sensors on factory floors. High-voltage medical equipment monitors patients in clinics or rehabilitation facilities. USB interfaces connect industrial machines to microprocessors. High-voltage relays operate according to instructions from intelligent controllers.
As mechanical industrial systems are increasingly replaced by motors, sensors, and actuators, machine-to-machine and human-to-machine interactions, such as those mentioned above, are becoming more prevalent. Bulky mechanical switches are being replaced by sensitive touch controls. Many motor applications operating at high voltages are also increasing. The use of semiconductor switches in high-voltage environments is also becoming more common. All of these applications require communication and interaction with intelligent controllers and actuators. The growing number of industrial, automotive, medical, and offline applications also necessitates the protection, noise reduction, and reliability performance provided by isolation technologies.
Isolators are essential for reliable and safe operation when properly applied. For example, isolators can prevent electric shock by isolating accessible circuitry of high-voltage or low-voltage processors, such as the C2000 microcontroller that drives high-power industrial motors.
Isolation solutions
In many industrial applications, efficient and reliable data transmission between isolation barriers at data transfer rates of hundreds of megabits or even higher, while preventing high-voltage surges, is required. Furthermore, data and power transmission is also necessary between certain isolation barriers in gate driver and industrial sensor applications. The increasing number of channels and the ever-growing demands for inter-channel isolation are also driving the need for miniaturized solutions.
Key attributes of integrated isolation technology
What exactly is isolation? An isolation barrier is a physical medium that facilitates the reliable exchange of data and/or power between two systems while blocking excess current.
Integrated isolation technology has several key attributes:
The maximum voltage that an isolator can withstand during a short period of time (surge voltage) or during normal operation (operating voltage).
The maximum rate of change of ground potential difference that an isolator can withstand without causing communication errors.
The delay between power supply pins is caused by the isolation barrier, direct distance (gap), and surface distance (leakage).
The degree of electromagnetic interference.
Multiple methods to achieve isolation technology
As more and more integrated devices are packaged into chips, individual capacitors and transformers are being replaced. Several common methods are as follows:
Capacitive isolation: Utilizing integrated capacitors with multilayer silicon oxide instead of individual capacitors, this provides a high level of isolation when transmitting data through an electric field. Our capacitive isolation technology uses two series capacitors on two chips placed side-by-side within the same module. This approach enables us to offer competitive enhanced isolation solutions for high data rate transmissions. Data rates exceeding hundreds of megabits per second can be achieved over the capacitive isolation barrier. Even higher data rates can be achieved through innovative circuit topologies, offering significant advantages for applications such as Industrial Ethernet. Our isolators leverage a range of advantages from customized CMOS technology to provide high-performance enhanced isolation barriers.
Inductive: A pair of coupled inductors can be used to isolate two circuits while exchanging data via magnetic flux. The two inductors can be embedded in a laminated printed circuit board or integrated monolithically on a die. A unique advantage of inductive isolation is the ability to transfer over hundreds of milliwatts of power across the isolation barrier without requiring an additional power supply on the sidewall. In addition to transferring data across the isolation barrier, efficient power delivery is also important for many industrial applications to achieve low input current and ensure sufficiently high maximum operating temperatures. TI digital isolators utilize integrated power technology, achieving the highest power delivery efficiency through innovative materials and inductor design.
Capacitive and inductive isolation are typically combined with data and/or power conditioning. Data conditioning minimizes the danger of transient spikes when they occur as data, helps isolate and protect signals, and ensures smooth operation of the device. Power conditioning optimizes power delivery efficiency.
Isolation can also be achieved by physically separating the two systems and using optical or electromagnetic wave communication.
A single isolation solution cannot meet all needs. In many cases, industrial applications require integrated solutions, including isolation amplifiers, high-speed data links that isolate signals such as RS-485, and isolated gate drivers. With increasing collaboration between humans and machines, high-voltage isolation solutions ensure more robust and reliable system operation.
